1. Field of the Invention
The present invention relates to a method of manufacturing a guide stent of a dental implant, and more particularly, to a method of manufacturing a guide stent of a dental implant, which is capable of diagnosing a dental implantation position according to obtained three-dimensional image information of periodontal tissue, guiding dental implantation in response to a diagnosed result, and improving surgical accuracy.
2. Discussion of Related Art
Generally, a dental implant is a implantation procedure in which a fixture formed of titanium or the like, so that the body does not react adversely, is implanted into an alveolar bone, from which a tooth falls out, so as to replace a lost tooth root, and then an artificial tooth is fixed thereto to restore a function of a tooth.
In the case of a prosthetic appliance or a denture, as time goes on, other teeth and bones therearound are eroded. However, the dental implant may prevent a damage of periodontal tissue therearound, and also may stably remove secondary dental caries production factors. Further, since the dental implant has the same structure as a natural tooth, there is no pain in the gums and feeling of irritation. Therefore, the dental implant has an advantage in that it may be semi-permanently used through continuous maintenance.
The dental implantation procedure is performed by forming a boring in the alveolar bone using a drill and then implanting the fixture in the boring. At this time, the forming of the boring and the implanting of the fixture may be different depending on a patient. This is because an implantation position, depth and direction of an implant should be determined in consideration of various factors such as a dental condition of a patient, a position of a tooth to be treated, and a condition of an alveolar bone of the patient.
Specifically, in a drilling operation for forming the boring in the alveolar bone, there is a problem in that it is very difficult for skilled operators as well as unskilled operators to precisely guess a drilling depth and direction during the operation. This is because it is not easy to determine a depth of the drilling operation when an operator performs the drilling operation by applying a force to the drill so as to form the boring in the alveolar bone, and also a nerve in the alveolar bone may be damaged when the drill is inserted over a certain depth.
In contrast, when the drilling operation is finished before reaching the certain depth, there may be some problems in which an excessive force due to a shallow boring depth may be exerted so as to fix the fixture, and also a screw thread around the boring may be damaged, or the fixture is not completely fixed, and thus a reoperation may be required.
Therefore, an assistant tool called a “guide stent” is used to find a precise position and direction in which the drilling operation is performed.
FIG. 1 is a flowchart illustrating a process of manufacturing a conventional guide stent.
As illustrated in FIG. 1, the conventional guide stent is manufactured in the following order. First, a female pattern of the periodontal tissue of a patient is obtained using a dental impression material formed of a rubber material (s1), and a plaster figure of the periodontal tissue of the patient is prepared by pouring plaster into the female pattern (s2).
Shapes of the tooth and the gum are obtained by a CT scan of the plaster figure (s2), and shapes of the alveolar bone and the tooth in the mouth are obtained by the CT scan on the patient (s3).
Then, the two images are matched with each other using a feature of the tooth or a feature of the plaster figure (s4). Further, a simulation is performed through image matched data, and a dental implant is planed (s5), and a guide stent capable of guiding the dental implant according to the plan is manufactured (s6).
At this time, the guide stent capable of guiding the dental implant should be manufactured by adding an operator's experience together with various anatomical conditions such as a thickness of the gum, a distribution of the alveolar bone, and a position of the target tooth of the patient. Therefore, it is more preferable to use exterior data of an oral organism than to use only direct data such as CT data.
To this end, a matching operation of matching each data with each other is essentially required. Conventionally, shape data of the plaster figure of the periodontal tissue in the mouth and the periodontal tissue data of the patient were matched based on the feature of the tooth. Alternatively, a method in which the plaster figure and a tray on which the plaster figure is seated are inserted into the mouth to obtain additional image data, and the image is matched based on a feature of the tray was used.
However, in the conventional image matching, since it takes an additional time to form the female pattern of the mouth shape of the patient and then to prepare the plaster model according to the female pattern, an entire operation time for the dental implant is increased. Further, since the female pattern and the plaster model corresponding to the patient should be prepared in every dental implantation procedure, an additional cost is generated, and thus economic efficiency in the dental implantation procedure is lowered.
Further, the image matching depends on accuracy of the plaster model. Therefore, in the case of the unskilled operator, accuracy of the image matching is lowered due to the low accuracy of the plaster model, and manufacturing ability irrelevant to medical ability is required. Furthermore, when the female pattern is manufactured, the accuracy of the female pattern is changed according to a biting force of the patient, elasticity of the gum, a tooth arrangement form and a tooth defect condition, and thus it is difficult to precisely and constantly manufacture the plaster model.
Therefore, the stent manufactured based on the inaccuracy plaster model is rough and unnecessarily thick. Thus, when the stent is inserted into the mouth of the patient, an opening angle of a jaw joint is increased, the jaw joint is strained and joint fatigue is increased, and also a space for the dental implantation procedure becomes narrow toward an inner side of the mouth, and thus difficulty in performing the dental implantation procedure is increased.
Further, since the accuracy of the guide stent is low, the fixture should be implanted into a previously formed boring, and high-priced custom abutment and crown (artificial tooth) should be manufactured according to a direction and an angle of the fixed fixture. Since the female pattern is obtained and then the custom abutment and the crown are designed, the number of hospital visits of the patient and a period of time until the dental implantation procedure is finished are increased.